Case sealing

Tapes

Gummed tapes

Gummed tapes are water-activated. They will adhere satisfactorily
to all packages made from paperboard. They will not work well on metals
or plastics. If "H" taping is used, and the tapes manufactured
from hard-sized Kraft paper and efficiently applied, they should provide
reasonable moisture and water-resisting properties, adequate for normal
transport hazards. Due to environmental pressures, Kraft paper gummed
tapes have gained in popularity, recently. For further details please
see Reinforced gummed - <ASTM
1974> Section 5.3.1

Pressure-sensitive tapes

Pressure-sensitive tapes are already activated and will
adhere satisfactorily to packages or containers made from paper, paperboard,
metal, glass or plastics. They are based on Regenerated cellulose film,
Cellulose acetate film, Polyvinyl chloride (PVA) film, Fabric and Moisture-resistant
paper. Such tapes need only the application of pressure to cause them
to adhere to almost any surface. Apart from seeing that the surface is
free from dust, oil, grease or moisture, no special preparation before
application is necessary. For further details
please see Pressure Sensitive Plastic - <ASTM
1974> Section 5.2.1. Clear tape is often to be recommended
for aesthetic reasons. Cases may be in different colors such as Kraft
or Mottled White. Labels and other markings that may be near or under
tape will still be legible. Difficulties in tape application or cutoff
will be less visible with clear tape.

Polypropylene tape recommendations:

Plastic Tape Spec

Minimum width:

2" (50mm)

Total thickness:

2.5 mil minimum

Tensile strength:

30 lb./in minimum

Heatfix or Thermo-sensitive tapes

Thermo-sensitive tapes are paper or fabric based and
heat activated. They will adhere satisfactorily to packages or containers
made from paper, paperboard, metal, glass or plastics. Such tapes, once
activated by heat, need only the application of pressure to cause them
to adhere. They are not used frequently in the corrugated field.

Tape Specifications

Case sealing tools and equipment vary and a variety
of paper reinforced and pressure sensitive plastic tapes are found in
common use. These may be specified interchangeably so long as a consistent
type of tape is used on each box and from box to box.

The following table aids in the selection of tape width
and application pattern on cases based on length of seam and weight of
package. Longer seams require wider tape to accommodate greater variation
in position, and greater deflection of joined panels across longer spans.
Concentrations in weight against a seam also indicate variation in the
straight seam application to an "H" pattern application.
ASTM D1974

Tape Width / Pattern as a Function of Weight and Length

Imperial Units

Length <16" (405mm)

Length 16" - 23.9" (405-609mm)

Length >=24" (610mm)

<10lbs (4.5Kg)

2" (50mm)

2" (50mm)

3" (75mm)

10 - 19.9lbs (4.5 - 9Kg)

2" (50mm)

2" (50mm)

3" (75mm)

20 - 29.9lbs (9.1 - 13.5Kg)

2" (50mm)

3" (75mm)

3" (75mm)

30 - 49.9lbs (13.6 - 22.5Kg)

3" (75mm) / H

3" (75mm) / H

3" (75mm)

>=50lbs (22.6Kg)

3" (75mm) / H

3" (75mm) / H

3" (75mm) / H

Width Conversions

U.S. Customary inches

Metric mm

Nominal mm

.5

12

.75

18

1

24

25

2

48

50

3

72

Patterns

Closure Method 2B1 - <ASTM
1974> Section 6.6.2.1  calls for 2" (50mm) pressure sensitive
film backed tape to be applied over the center seams of the box and continuing
at least 2" (50mm) onto the ends of the box. A variation of this
method, determined by the table above, calls for 3" (75mm) tape to
be used with the tape continuing at least 2.5" (60mm) onto the ends
of the box.

Tape closure method 2B1

Closure Method 2B7 - <ASTM
1974> Section 6.2.2.7  calls for 2" (50mm) pressure sensitive
film backed tape to be applied over the center seams of the box and continuing
at least 2" (50mm) onto the ends of the box. 4 additional strips
shall be applied over the seam formed by the edges of the outer flaps
and the end panels and extend to within Ÿ" (20mm) of the corners
of the box.

Other Pack Sealing Methods

Strapping

Steel or Plastic strapping are often used for: Bundling,
Palletizing, Unitizing, Reinforcing, Closing and Bailing. Polypropylene
or Nylon strapping is what is most commonly used for pack sealing. The
advantages are a strong and secure seal, however, it lacks ascetic appeal.
However, when used with cases strapping can be very useful for tamper
evidence and is particularly good when used on multiple depth cases, that
can be difficult to deal with using standard gluing and taping machinery.

Stapling

King size staples are also used for sealing corrugated
cases. These large performed staples are clinched on a retractable anvil,
thus enabling the case to be closed after it has been packed. The main
advantages are: economy and speed of closure, security and efficiency
- no problems with storing pre-sealed cases or drying time. However, they
are less suitable for sensitive or food uses.